A motorway collapse in Genoa, northern Italy, has killed at least 35 people and left more injured after a 650ft section of bridge crushed cars below.

Around 20 vehicles plunged nearly 150ft into a heap of rubble after a huge section of the Morandi Bridge collapsed over an industrial zone in the port city, sending tonnes of twisted steel and concrete debris onto warehouses below.

Rescuers say at least 35 are confirmed to have been killed. Four survivors are known to have been pulled from the collapse debris, which authorities say was caused by ‘structural weakness’.

At least 35 people have been killed after the bridge collapse in northern Italy (PA)

Rescuers rush to the scene in northern Italy. (Reuters)

Emergency services said the bridge collapsed due to ‘structural weakness’ (PA)

The area where the motorway viaduct collapsed in Genoa, northern Italy. (AFP)

Maria Luisa Catalano, a police official in Genoa, said authorities are still involved in rescue efforts.

Two of the victims were in their homes when the bridge collapsed, according to Sky News Italy.

One woman, believed to be 75-years-old, reportedly died as a result of smoke inhalation after a fire from the bridge while a man in his 30s suffered severe head trauma.

Rescuers next to the bridge show the scale of the disastrous collapse on Tuesday. (Rex)

Wreckage: A huge chasm of debris is left behind after 650ft of the bridge crumbled. (Rex)

Destroyed: A lorry lies crushed amongst the rubble. (Rex)

The disaster occurred on a highway that connects Italy to France and other resorts on the eve of Ferragosto, a major Italian holiday, and traffic would have been heavier than usual as many people travelled to beaches or mountains.

Eyewitness footage video appeared to capture the sound of a man screaming: ‘Oh god, oh, god.’

One man claimed to have seen bridge oscillate more than usual this morning.

Huge piles of rubble jut from the water after the bridge collapse in the northern Italian port city (PA)

Rescuers work among the rubble of the collapsed Morandi highway bridge (PA)

He told local Italian newspaper Il Secolo XIX: ‘I walk the Morandi Bridge almost every day.

‘The bridge often oscillates, for trucks, the tails… but this morning I had the feeling, maybe just the suggestion, that this oscillation was much more marked than usual.

‘I walked back to the house on my way back a quarter of an hour before it collapsed.’

He said: ‘The first information would seem to say that the maintenance had been made but it can not be so. These tragedies can not happen in a civilised country like Italy.

Vehicles can be seeing lying devastated on the ground following the bridge collapse (Reuters)

Concrete and rubble litter the ground (Reuters)

At least ten vehicles were said to have been involved in the collapse (PA)

‘The maintenance comes first of all and those responsible will have to pay up to the last. hours we will have more information.’

Broadcaster Sky TG24 said the section of the bridge collapsed over an industrial zone. Firefighters have raised concerns about gas lines.

Photos published by the ANSA news agency on its website showed a huge gulf between two sections of the bridge.

Video captured the sound of a man screaming: “Oh god, oh, god.” Other images showed a green truck that had stopped just yards short of the gaping hole in the bridge.

Emergency services survey the damage of the collapse (Reuters)

A rescue helicopter surveys the scene of rubble below (PA)

Eyewitness footage shows the remains of the collapsed bridge in Genoa (Facebook/sosemergenza)

Interior minister Matteo Salvini said some 200 firefighters were responding to the accident.

He said on Twitter: “We are following minute by minute the situation for the bridge collapse in Genoa.”

The Morandi Bridge was inaugurated in 1967. It is 295ft high and just over three-quarters of a mile long, with the longest section between supports measuring 650ft.

The bridge is a main thoroughfare connecting the A10 highway heading towards France and the A7 highway that continues north towards Milan.

The collapse of the bridge comes eight days after another major accident on an Italian highway, near the northern city of Bologna.

In that case, a tanker truck carrying a highly flammable gas exploded after rear-ending a stopped truck on the road before it was hit from behind itself. The accident killed one person, injured dozens and blew apart a section of a raised eight-lane highway.